Function insertBetweenImmediateChildren

packages/cli/src/transform.ts:1200–1226

(
  node: any,
  leftChildIndex: number,
  rightChildIndex: number,
  insertion: string,
  existingBoundaryText = "",
)

}

function insertBetweenImmediateChildren(
  node: any,
  leftChildIndex: number,
  rightChildIndex: number,
  insertion: string,
  existingBoundaryText = "",
): boolean {
  const children = node.children;
  if (!children || !insertion) return false;

  const leftChild = children[leftChildIndex];
  const rightChild = children[rightChildIndex];
  if (/^\s+$/.test(insertion) && /^\s*$/.test(existingBoundaryText)) {
    const totalSpaces = existingBoundaryText.length + insertion.length;
    children.splice(rightChildIndex, 0, ...createWhitespaceInsertionNodes(Math.max(1, totalSpaces)));
    return true;
  }

  const preferExplicitBoundary = leftChild?.type !== "JSXText" || rightChild?.type !== "JSXText";
  if (!preferExplicitBoundary && rightChild?.type === "JSXText" && leftChildIndex + 1 === rightChildIndex) {
    rightChild.value = insertion + rightChild.value;
    return true;
  }

  children.splice(rightChildIndex, 0, createInsertionNode(insertion));
  return true;
}

/**
 * Replace text that spans across multiple child elements.